FIELD OF THE INVENTION
The present invention relates to a bulk container having a base with side and end panels that are pivotally mounted to the base. The panels lie flat during shipment, and then are uprighted and joined at their corners to form end and side walls of the container when the container is assembled for use. The container is stackable during shipment in its unassembled state and stackable in use, and further assembled and unassembled containers can be interstacked.
Knock down bulk containers are known, and have the advantage that the side and end walls of the container can be erected when the container is to be used, but otherwise the container can be shipped or stored in an unassembled state to save space.
Conventional bulk containers of the knock down type suffer from many disadvantages, particularly with regard to manufacturing the container in a minimum number of pieces that can be efficiently assembled together, both in the initial assembly of the container when it is formed in the knock down state, and in the final steps of assembly when the container is erected for use. The container parts are molded of a synthetic resin material. In the initial assembly steps, the side and end panels are hinged to the base along its edges. These hinged joints must then function to permit the side and end panels to be swung into an upright position in the steps performed later to assemble the container for use. Furthermore, the hinged joints must withstand the loading forces of the material contained within the bulk box once it is assembled.
Knock down or collapsible type containers also suffer from the disadvantage that they are difficult to assemble when they are ready to be used. In particular, the connecting structure provided to form the corner joints is frequently difficult to assemble in that more than one person is required to complete the task, thereby detracting from the efficient assembly of the container by the end user.